I second Jon Mixon here, but I would say there are more places that you should not hide things.
- Bibles- seriously, of all the books to hide money in, the Bible is the most obvious and therefore the worst
- Socks- the amount of people who 'hide' cash in their sock to avoid muggers taking it is ridiculous. Just give them the cash, its not worth your life
- Any drawers, cupboards, etc- a thief will open ...